System and method for I-Q imbalance correction

摘要

Systems and methods are disclosed for compensating I-Q imbalance in a wireless receiver. The receiver may employ a quadrature downconverter configured to receive an RF signal input and output an in-phase component and a quadrature component at an IF, an IF rotation block configured to downconvert the in-phase and quadrature components to baseband and an I-Q correction block configured to compensate for an I-Q imbalance in the received signal, wherein the I-Q correction block is positioned downstream from the IF rotation block in the signal path. Performing the I-Q correction after conversion to baseband may allow the compensation calculations to operate at a reduced digital rate. Similarly, digitally adjusting the gain of the signal prior to I-Q compensation may reduce the number of bits that are manipulated during the compensation process. These features may represent significant efficiencies as compared to I-Q corrections performed at IF.

主权项

1. A digital wireless receiver for receiving a data signal, wherein the receiver has a signal path comprising a quadrature downconverter configured to receive a radio frequency (RF) signal corresponding to the data signal and output an in-phase component and a quadrature component at an intermediate frequency (IF), an IF rotation block configured to downconvert the in-phase component and quadrature component to baseband and an in-phase (I)-quadrature (Q) correction block configured to compensate for a modeled I-Q imbalance in the received signal, wherein the I-Q correction block is positioned downstream from the IF rotation block in the signal path;
wherein upconversion of the data signal to IF is modeled by a matrix A and wherein the IF rotation block is configured to perform an operation corresponding to multiplication by an inverse of matrix A, matrix A−1; wherein the I-Q imbalance is modeled as a matrix B and wherein the I-Q correction block is configured to perform a matrix multiplication by A−1B−1A.